An FSA (Flexible Spending Account) and an HSA (Health Savings Account) are tax-advantaged accounts for medical expenses but differ in key aspects.

FSAs, employer-sponsored, allow employees to use pre-tax dollars for medical expenses such as prescriptions and copays, but typically feature a "use-it-or-lose-it" policy where funds must be used within the plan year.

HSAs are available to those with a high-deductible health plan and offer more flexibility, allowing funds to roll over annually.

For more information, see Flex’s Comprehensive Guide to HSA/FSAs.

This means that product is not eligible for this payment method.

Like any credit or debit card, HSA/FSAs can be declined if any of the data from the card is incorrect (number, expiration date, zip code etc).

Flex will alert you in checkout if any of these fields is missing or incorrect so you can update them.The most common reason for rejection of the card is insufficient funds.

Reach out to your HSA or FSA provider to verify the amount of money in your account before attempting to complete your purchase again.

A Letter of Medical Necessity (LMN) is a document written by a healthcare provider that explains why a specific medical service, treatment, or equipment is necessary for a patient's health.

In relation to an HSA (Health Savings Account) or FSA (Flexible Spending Account), an LMN is often required for reimbursement of expenses that are not clearly defined as eligible under the standard IRS guidelines.